Arrangement for heat discharge, particularly for ultrasonic transducers with high performance

ABSTRACT

The invention relates to a heat dissipating device, especially for high-performance industrial ultrasonic transducers. The aim of the invention is to produce a device that enables high-performance ultrasonic transducers to operate continuously in environments with high heat and/or high humidity, whereby heat is dissipated in an explosion-proof embodiment in a more effective manner. This is achieved by surrounding the ultrasonic transducer ( 1 ) with a closed cooling system comprising a layer ( 2 ) that absorbs vibrations, e.g. a silicon rubber layer, and a layer that dissipates heat ( 3 ), e.g. silica sand.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/EP99/05535 which has an Internationalfiling date of Aug. 2, 1999, which designated the United States ofAmerica.

DESCRIPTION

The invention concerns an arrangement for heat discharge, particularlyfor ultrasonic transducers with high performance rating for theindustrial application.

It is generally known to cool ultrasonic transducers with high capacityrating for the purpose of discharging heat which occurs as a result ofthe conversion of the electric energy into mechanical energy by means ofinternal friction in the piezoelectric elements and by means of electriclosses.

In many cases the known cooling systems consist only of a casing whichencloses the ultrasonic transducer, such casing having openings (ports)through which heat is withdrawn by means of convection (prospectus ofMessrs Bandelin electronic “Sonorex” Ultrasonic Disintegrators”,Sonopuls HD 60). This type of cooling is insufficient for highperformance ratings.

With an additional cooling by means of a fan, dust and moisture istransported into the casing and the danger of electric short-circuitscaused by bridge formation increases.

The withdrawal of heat by way of a horn-flange-casing-connection mountedat the ultrasonic transducer is also known, where the heat discharge iseffected by way of a copper cooling plate for water cooling (prospectusof Messrs TELSONIC “Ultrasonic High Performance Reactor, Series SRR”).In this case also, the heat discharge for high performance ratings andcontinuous operation is insufficient. In addition to the poor heatconductivity of titanium, and where this arrangement is concerned, onlya narrow connection to the horn at the location of a vibration node(zero point) can be realised in order to create a vibration-disengagedtransition. With this, there is only a minor heat transfer from the heatsource to the cooling system which is not sufficient for the continuousoperation at high performance levels. A transfer of vibrations to thecooling system is to be avoided as capacity is lost and a further heatincrease would result.

Further numerous variants of the cooling are known where, for example,the casings are provided with air cooling or with high-pressure air.These systems also indicate the danger of electric short-circuit. Closedsystems with fans and heat exchange from the inside to the outside arealso known. However, these are sophisticated from equipment-technicalaspects and allow only a limited heat withdrawal.

In DE 43 39 786 A1 an arrangement for heat discharge is described where,for the purpose of heat discharge of electronic components immediatelyon the surface of the casing of the electronic component aheat-conductive plastic form body made from a silicone polymer isenvisaged which has a surface contact with the casing that also servescooling purposes.

In DE 35 28 291 A1 an arrangement is stated for the cooling ofelectronic structural elements where bulk material takes over the heattransfer from the components to the cooling bodies. Sand or glass pearlshaving a certain grain sizing are envisaged as a bulk material.

These arrangements also require a sophisticated cooing system withcooling bodies, and have the disadvantages associated with these.

A disadvantageous factor with all known solutions is the fact that thecontinuous operation of ultrasonic transducers at high performancelevels, particularly in explosion-protected design or for types to beused in moist ambient surroundings, cannot be ensured without majorexpenditure and/or without a worsening of the efficiency.

The task assignment of the invention is to develop an arrangement forheat discharge, particularly for ultrasonic transducers with highperformance ratings which reliably warrants the continuous operation ofthe ultrasonic transducer, with high performance, also in ambientsurroundings with high moisture levels and/or heat and in anexplosion-protected design by means of a more effective heat withdrawalthat has been known up to the present.

The solution to this task assignment results from the features of claim1. By means of the closed cooling system enclosing the ultrasonictransducer, this said cooling system consisting of a thinvibration-absorbing elastic layer such as silicone caoutschouc and aheat discharging layer such as quartz sand, a status is achieved whereno mechanical losses occur during the transfer of heat capacity becausethe vibration-absorbing layer does not transfer any vibrations to thefollowing layers. The direct application of the layers onto theultrasonic transducer produces an effective large-surface heat dischargewithout having considerably complex equipment which is susceptible todisturbances at the same time.

Purposeful developments of the invention are stated in the Subclaims.

The invention is explained in greater detail in an embodiment of anarrangement for heat discharge for an ultrasonic transducer as shown ona drawing. The following items are shown:

FIG. 1: a schematic cross-sectional illustration of the ultrasonictransducer with cooling system, and

FIG. 2: the section A—A through the ultrasonic transducer according toFIG. 1.

For high-performance ultrasonic transducers in the kW-range, the heatdischarge is of great significance in order to ensure safe and reliablecontinuous operation in industrial plants.

From the sectional view in FIG. 1 and the detail illustration in FIG. 2,the arrangement of the cooling system for an ultrasonic transducer isrecognisable.

The surface of the ultrasonic transducer 1 is coated with an elasticvibration-absorbing layer 2, for example of silicone caoutschouc, in alayer thickness of 0.05 mm to 0.5 mm for example.

This layer 2 picks up the vibrations radiated from the ultrasonictransducer and absorbs them in such a way that no vibrations occur onthe surface of the layer 2.

A heat-conducting layer 3 is applied to layer 2. This heat-conductinglayer 3 can consist of quartz sand for example and can have, forexample, a thickness of between 0.2 and 2 mm. The heating of theultrasonic transducer 1 is discharged by way of its entire surface tolayer 2 and from there it is discharged to layer 3.

The heat-conducting layer 3 is again joined in close contact with acasing 4, for example of aluminium continuous casting, which can havecooling fins and an external enclosure. Heat-conducting media such asair, water or oil or similar substances can be located between thecooling fins. In addition, it is also possible to withdraw heat fromlayer 3 in the known manner by means of ventilation or by means of anyother known cooling systems.

The invention is not limited to the embodiments described here.Moreover, it is possible to realise further embodiments by means of acombination of the features without departing from the framework of theinvention.

SUMMARY

The invention refers to an arrangement for heat discharge, particularlyfor ultrasonic transducers with high performance rating for theindustrial application.

The task assignment of the invention, to develop a category-relatedarrangement which warrants the continuous operation of ultrasonictransducers with high performance ratings also in surroundings with highmoisture and/or heat levels and in explosion-protected design by meansof a more effective heat discharge than known up to the present, issolved in such a way that the ultrasonic transducer 1 is surrounded by aclosed cooling system which has a vibration-absorbing layer 2 such assilicone caoutschouc and a heat-withdrawing layer 3 such as quartz sand.

What is claimed is:
 1. Arrangement for heat discharge for ultrasonictransducers wherein, a vibration-absorbing elastic layer, that is indirect contact with the surface of the ultrasonic transducer, and a heatdischarging layer of a particle-spreadable material, that is in directcontact with the elastic layer, form a cooling system that surrounds thetransducer to be cooled.
 2. Arrangement according to claim 1, wherein,the heat discharging layer, that is in direct contact with the elasticlayer, is joined in close contact with a casing for wide surfacedischarge of the heat to the outside.